1. Field of the Invention
The present invention relates to a multi-laser projection device and to a corresponding production method.
2. Description of the Related Art
Multi-laser projection devices, having for example three laser diodes having different wavelengths (red, green, blue), are known, for example, from published German patent application document DE 10 2007 042 720 A1.
FIG. 5 is a schematic cross-sectional representation of a multi-laser projection device for the explanation of the problem on which the present invention is based.
In FIG. 5, reference character 9 designates a multi-laser projection device that has three laser diodes LD1, LD2, LD3 for producing light having different wavelengths (red, green, blue).
Laser diodes LD1, LD2, LD3 are standardly installed in TO housings, but in principle can also be processed as blank chips. The direction of the light paths formed by laser diodes LD1, LD2, LD3 are shown in dashed lines.
The divergent light emitted from laser diodes LD1, LD2, LD3 is collimated by a respective discrete first collimator lens 1, 2, 3 along a first collimation axis, and is subsequently collimated, using a respective second discrete collimator lens 4, 5, 6, in a second collimation axis situated perpendicular to the first collimation axis.
The light collimated in this way of laser diodes LD1, LD2, LD3 then passes through an entry surface E into a beam combiner 7, where it is precisely superposed. Finally, the superposed light exits through an exit surface A from beam combiner 7 into a deflection unit (scanner) 8, which moves the laser beam formed in this way over a projection surface (not shown).
The components of multi-laser projection device 9 are mounted in a common housing 90.
For the assembly of multi-laser projection device 9 shown in FIG. 5, first the components LD1, LD2, LD3, 1, 2, 3, 4, 5, 6, and 7 are individually adjusted and fixed relative to one another. This standardly takes place during active operation of the respective laser diode LD1, LD2, LD3 in order to make it possible to directly observe the collimation result of collimator lenses 1, 2, 3, 4, 5, 6. The finally adjusted and fixed assembly 10 is then adjusted relative to pre-mounted deflection unit 8, and is fixed in housing 90.
In this assembly technique, therefore, the optical components of multi-laser projection device 9 are individually adjusted in a common assemblage of assembly 10, which is expensive.
FIG. 6 is a schematic cross-sectional representation of a further multi-laser projection device for the explanation of the problem on which the present invention is based.
In FIG. 6, the multi-laser projection device is designated 9′. In the assembly technique illustrated in FIG. 6, individual laser diodes LD1, LD2, LD3 are each actively adjusted with their respective first collimator lens 1, 2, 3 and their respective second collimator lens 4, 5, 6, and are pre-mounted in a respective assembly 11a, 11b, 11c. 
Subsequently, each assembly 11a, 11b, 11c is actively adjusted relative to beam combiner 7, i.e. while in laser emission operation, and is fixed in housing 90 of multi-laser projection device 9′.
In the two assembly techniques described with reference to FIGS. 5 and 6, therefore, for each laser diode LD1, LD2, LD3 a plurality of optical components must be actively adjusted, which is the cause of a large part of the production expense of multi-laser projection device 9 or 9′.